1. Field of the Invention
Generally, the invention relates to light sources for flashlights. More specifically, the invention relates to such light sources wherein at least one light emitting diode produces the light which is subsequently collimated into a beam of light.
2. Description of the Prior Art
It is estimated that in 1998 over two hundred (200) million collimating reflector type flashlights were produced. Conventionally known flashlights which utilize a collimating reflector operate with incandescent lamps (bulbs) which have a filament placed in a geometric position compatible with the focal point of the collimating reflector.
Incandescent lamps (bulbs) are constructed with a xe2x80x98light center lengthxe2x80x99 or LCL which is defined as the best strait line that can be passed through the majority of the lighted coil. A collimated beam of light, defined by xe2x80x98beam candle powerxe2x80x99, is created when the coil is properly positioned to a focal point of the collimating reflector.
As a source of illumination, conventional light emitting diodes are generally limited to small flashlights such as key chain type lights, small pen lights and small flashlights which do not utilized collimating reflectors to enhance the collimation of the produced light. This is due primarily to the narrow view angle of the produced light and the lack of utilization of light bending surfaces or other diffusion methods. Attempts have been made to use light emitting diodes in incandescent lamp bases. These attempts generally have been limited to providing a convenient light source for use in existing flashlights where the produced light does not interact with the collimating reflector of those flashlights. It is important to note that these replacement incandescent lamps using light emitting diodes were not designed to operate with the collimating reflector to produce a beam of light prior to applicants invention.
Conventional, narrow projection angle, light emitting diode light sources lack light bending surfaces to broaden the narrow view angle of the produced light. The light emitting diode, in conventional form, does not make a satisfactory source of light for conventional flashlights because the point source of light is on a plane. The conventional light emitting diode is formed by the deposition of semiconductor materials and phosphors to a substrate in a planar configuration which inhibits use as a broad spectrum light source. Conventional collimating reflector flashlight require the broad spectrum light source.
The Polar light distribution of conventional light emitting diodes is at best one hundred and twenty-five (125) degrees and most commonly fifteen (15) degrees. Conventional collimating reflector flashlights require a polar distribution of three hundred and sixty (360) degrees, (radially), for maximum efficiency.
Some progress has recently been made to provide for a widening of the projection angle of light emitting diodes. A principle method of widening the projection angle of light emitting diodes involves placement of the light emitting diode chip within a tiny cup or bowl reflector base. Work in this area has resulted in widening the projection angle from the common fifteen (15) degrees to as much as one hundred and twenty (120) degrees and slightly beyond. Typically phosphor, or another suitable material, is used as a coating over the light emitting diode chip which then acts to diffuse the light produced by the light emitting diode chip to enable the tiny reflector base to widen the projection angle. These new style light emitting diode chips are ideally suited for use with the present invention.
Both the conventional light emitting diodes and the new style coated light emitting diodes use an acrylic or plastic molded lens package without any indices of refraction or other diffusing methods.
Various methods exist in the art to alter the angle of projection of light. Such conventional methods to alter the angle of projection of light include lighted panels and annunciators, amongst others. Your applicant is unaware of utilization of such methods with light emitting diode light sources wherein the produced light may be efficiently used with flashlights having a conventional collimating reflector.
Light emitting diodes which produce white light, offer a new and superior light source for collimating reflector type flashlights in that they provide superior lamp life and battery run time. Conventional light emitting diode light sources are unsatisfactory for direct use in flashlights with collimating reflectors due to a narrow viewing angle of the light emitting diode, generally between fifteen (15) degrees and thirty (30) degrees. When the conventional light emitting diode is positioned facing away from the collimating reflector, this narrow viewing angle projects the available light beyond the walls of the collimating reflector. When the conventional light emitting diode is positioned facing toward the collimating reflector, this narrow viewing angle projects the available light to only a portion of the wall of the collimating reflector. The curved collimating reflector wall therefore cannot properly act upon the produced light of conventional light emitting diode light sources to collimated the light beam. The new style light emitting diodes which produce wider projection angles suffer similar deficiencies to those experienced by conventional light emitting diodes.
For the above mentioned reasons, mere substitution of a light emitting diode light source for the conventional incandescent lamp in flashlights, where the flashlight has a curved collimating reflector, will fail because the substitute light emitting diode light source and the existing curved collimating reflector will fail to cooperate to produce an acceptable collimated light beam.
Light emitting diodes are superior to conventional incandescent lamps (bulbs) because they: 1) require less power, 2) have a longer life, 3) have a greater resistance to both shock and vibration and 4) provide generally higher color temperature.
Due to the long life of the light emitting diode light source it is conceivable that a flashlight having a light emitting diode as the light source would never require replacement of the light source. Due to the lower power requirement of the light emitting diode light source, batteries of such flashlights would last up to 10 times as long as batteries of conventional incandescent flashlights. This combination provides for considerable cost and environmental savings.
Efforts have been made to provide for a flashlight having a suitably narrow projection beam of light which utilize light emitting diodes as the light source. These efforts avoid use of a collimating reflector and rely upon projection of the light from the light emitting diode directly onto an optical focusing lens which then projects the light passing therethrough into the narrow projection beam of light. Such flashlights, while producing an acceptable beam of light, are extremely expensive to manufacture when compared to collimating reflector type flashlights due to the expense involved with manufacture of the optical focusing lens. For this reason such flashlights are not considered applicable to the present invention.
A great need exists for collimating reflector type flashlights which have low current draw, long life and which are inexpensive to manufacture. Numerous attempts have been made to produce collimating reflector type flashlights which have the desired low current draw, long life and low manufacturing costs. These attempts have been less efficient than desired. The present invention substantially fulfills these needs. Utilization of the designs of the present invention will fill a long felt need and create a new market niche.
In view of the foregoing disadvantages inherent in the known types of light sources for flashlights, your applicant has devised a method of positioning a light dispersion location of a light emitting diode lamp (bulb) assembly at a relative elevated position generally matching a relative elevated position of a filament of a conventional incandescent lamp when placed in identical flashlights. Various methods may be employed to radially disperse the produced light at the light dispersion location to more closely match the dispersion pattern of the conventional incandescent lamp.
My invention resides not in any one of these features per se, but rather in the particular combinations of them herein disclosed and it is distinguished from the prior art in these particular combinations of these structures for the functions specified.
There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto. Those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
It is therefore a primary object of the present invention to provide for use of light emitting diodes as practical light sources for conventional collimating reflector type flashlights.
Other objects include;
a) to provide for use of a diffuser unit to spread the light produced by light emitting diodes to a wide angle of projection.
b) to provide for diffuser units having textured surfaces to provide for the wide angle of projection of light produced by light emitting diodes.
c) to provide for diffuser units having multi-faceted surfaces to provide for the wide angle of projection of light produced by light emitting diodes.
d) to provide for placement of a light dispersion location within a lamp assembly which closely matches a light center length, LCL, of a conventional incandescent lamp.
e) to provide for use of multiple light emitting diodes in lamp assemblies.
f) to provide for a combination of a reflector base, a diffuser unit to cover the reflector base and a plurality of light emitting diodes positioned between the reflector base and the diffuser unit to provide for a uniform wide angle distribution of produced light.
g) to provide for color mixing of blue light, green light and red light each produced by a unique light emitting diode chip to produce a visibly acceptable white light.
h) to provide for a lamp assembly having at least one light emitting diode as the light source where the lamp assembly may be installed in a collimating reflector type flashlight as a direct replacement for existing incandescent lamps.
i) to provide for a lamp assembly utilizing a light emitting diode as a light source where the lamp assembly is shaped similarly to existing incandescent lamps.
j) to provide for an extension of a battery power supplies life by utilizing a light emitting diode as the light source for a collimating reflector flashlight compared to the life of the battery power supply when utilizing an incandescent lamp.
k) to provide for an extension of a lamp assemblies life span by utilizing a light emitting diode as the light source for a collimating reflector flashlight compared to the life of an incandescent lamp.
l) to provide for a doping, or coating, of a conventional blue light emitting diode chip utilizing a mixture of red phosphor and green phosphor and blue phosphor to produce a visibly acceptable white light.
These together with other objects of the invention, along with the various features of novelty which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated the preferred embodiments of the invention.